A study that has recently gone to press (Bilaut et al., in press) suggests that elite freediving may cause mild, but persistent short term memory loss. The study subjected elite freedivers (>6 min static breath hold), novice freedivers (>4 min static breath hold) and a control group to specific psychological tests.
The time to complete the tests was positively correlated with freediving static performance. In simple words this suggests that a better breath-hold means a slower brain.
Memory loss: reserved for the elite?
More specifically it was the elite breath hold divers that showed poorer performance on the tests. They took longer to complete the tests and made more mistakes. Novice freedivers and the control group showed normal performance.
The divers had not done any apnea prior to the test, nor had they had blackouts or LMCs in the week prior to the tests. Interestingly, there was no correlation between the total amount of blackouts and LMCs and the freedivers’ performance on the tests.
The authors speculate that the improved static time is not the cause of the poorer performance. Instead the static time is an indicator of the amount of hypoxia that the athletes face during training. More hypoxic intervals over the course of a diving career may lead to “mild, but persistent” memory loss.
The results are in contrast to a previous study by Ridgway and McFarland (2006). This study did not indicate long-term cognitive impairments in freedivers.
- Billaut, F., Gueit, P., Faure, S., Costalat, G., Lemaître, F., Do elite breath-hold divers suffer from mild short-term memory impairments? (In press) Applied physiology, nutrition and metabolism
- Ridgway and McFarland (2006). Apnea diving: long-term neurocognitive sequelae of repeated hypoxemia. The clinical neuropsychologist, 20:160-176